// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_TASK_SCHEDULER_SEQUENCE_SORT_KEY_H_
#define BASE_TASK_SCHEDULER_SEQUENCE_SORT_KEY_H_

#include "base/base_export.h"
#include "base/task_scheduler/task_traits.h"
#include "base/time/time.h"

namespace base {
namespace internal {

    // An immutable but assignable representation of the priority of a Sequence.
    class BASE_EXPORT SequenceSortKey final {
    public:
        SequenceSortKey(TaskPriority priority, TimeTicks next_task_sequenced_time);

        TaskPriority priority() const { return priority_; }

        bool operator<(const SequenceSortKey& other) const;
        bool operator>(const SequenceSortKey& other) const { return other < *this; }

        bool operator==(const SequenceSortKey& other) const
        {
            return priority_ == other.priority_ && next_task_sequenced_time_ == other.next_task_sequenced_time_;
        }
        bool operator!=(const SequenceSortKey& other) const
        {
            return !(other == *this);
        };

    private:
        // The private section allows this class to keep its immutable property while
        // being copy-assignable (i.e. instead of making its members const).

        // Highest task priority in the sequence at the time this sort key was
        // created.
        TaskPriority priority_;

        // Sequenced time of the next task to run in the sequence at the time this
        // sort key was created.
        TimeTicks next_task_sequenced_time_;
    };

} // namespace internal
} // namespace base

#endif // BASE_TASK_SCHEDULER_SEQUENCE_SORT_KEY_H_
